Change "Pylance not installed" prompt to allow reverting to Jedi

package.nls.json

@@ -49,9 +49,11 @@
     "Pylance.proposePylanceMessage": "Try out a new faster, feature-rich language server for Python by Microsoft, Pylance! Install the extension now.",
     "Pylance.tryItNow": "Try it now",
     "Pylance.remindMeLater": "Remind me later",
-    "Pylance.installPylanceMessage": "Pylance extension is not installed. Click Yes to open Pylance installation page.",
     "Pylance.pylanceNotInstalledMessage": "Pylance extension is not installed.",
     "Pylance.pylanceInstalledReloadPromptMessage": "Pylance extension is now installed. Reload window to activate?",
+    "Pylance.pylanceRevertToJediPrompt": "The Pylance extension is not installed but the python.languageServer value is set to \"Pylance\". Would you like to install the Pylance extension to use Pylance, or revert back to Jedi?",
+    "Pylance.pylanceInstallPylance": "Install Pylance",
+    "Pylance.pylanceRevertToJedi": "Revert to Jedi",
     "Experiments.inGroup": "User belongs to experiment group '{0}'",
     "Experiments.optedOutOf": "User opted out of experiment group '{0}'",
     "Interpreters.RefreshingInterpreters": "Refreshing Python Interpreters",

package.nls.ru.json

@@ -34,7 +34,6 @@
     "Pylance.proposePylanceMessage": "Попробуйте новый языковый сервер для Python от Microsoft: Pylance! Установите расширение Pylance.",
     "Pylance.tryItNow": "Да, хочу",
     "Pylance.remindMeLater": "Напомните позже",
-    "Pylance.installPylanceMessage": "Расширение Pylance не установлено. Нажмите Да чтобы открыть страницу установки Pylance.",
     "Pylance.pylanceNotInstalledMessage": "Расширение Pylance не установлено.",
     "Pylance.pylanceInstalledReloadPromptMessage": "Расширение Pylance установлено. Перезагрузить окно для его активации?",
     "LanguageService.reloadAfterLanguageServerChange": "Пожалуйста, перезагрузите окно после смены типа языкового сервера."

package.nls.zh-cn.json

@@ -49,7 +49,6 @@
     "Pylance.proposePylanceMessage": "试试微软新的更快的、功能丰富的语言服务器 Pylance! ",
     "Pylance.tryItNow": "立即安装",
     "Pylance.remindMeLater": "稍后提醒",
-    "Pylance.installPylanceMessage": "Pylance 扩展未安装。点击 \"是\" 打开 Pylance 安装页面。",
     "Pylance.pylanceNotInstalledMessage": "Pylance 扩展未安装。",
     "Pylance.pylanceInstalledReloadPromptMessage": "Pylance 扩展未安装。重新加载窗口以激活？",
     "Experiments.inGroup": "用户属于 '{0}' 实验组",

src/client/activation/activationService.ts

@@ -86,6 +86,8 @@ export class LanguageServerExtensionActivationService
             this.serviceContainer.get<IExtensions>(IExtensions),
             this.serviceContainer.get<IApplicationShell>(IApplicationShell),
             this.serviceContainer.get<ICommandManager>(ICommandManager),
+            this.serviceContainer.get<IWorkspaceService>(IWorkspaceService),
+            this.serviceContainer.get<IConfigurationService>(IConfigurationService),
         );
         disposables.push(this.languageServerChangeHandler);
     }

src/client/activation/common/activatorBase.ts

@@ -42,7 +42,7 @@ export abstract class LanguageServerActivatorBase implements ILanguageServerActi
     protected resource?: Resource;
     constructor(
         protected readonly manager: ILanguageServerManager,
-        private readonly workspace: IWorkspaceService,
+        protected readonly workspace: IWorkspaceService,
         protected readonly fs: IFileSystem,
         protected readonly configurationService: IConfigurationService,
     ) {}

src/client/activation/common/languageServerChangeHandler.ts

@@ -1,27 +1,43 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-import { Disposable } from 'vscode';
-import { IApplicationShell, ICommandManager } from '../../common/application/types';
+import { ConfigurationTarget, Disposable } from 'vscode';
+import { IApplicationShell, ICommandManager, IWorkspaceService } from '../../common/application/types';
 import { PYLANCE_EXTENSION_ID } from '../../common/constants';
-import { IExtensions } from '../../common/types';
+import { IConfigurationService, IExtensions } from '../../common/types';
 import { createDeferred } from '../../common/utils/async';
 import { Common, LanguageService, Pylance } from '../../common/utils/localize';
 import { LanguageServerType } from '../types';
 
 export async function promptForPylanceInstall(
     appShell: IApplicationShell,
     commandManager: ICommandManager,
+    workspace: IWorkspaceService,
+    configService: IConfigurationService,
 ): Promise<void> {
-    // If not installed, point user to Pylance at the store.
     const response = await appShell.showWarningMessage(
-        Pylance.installPylanceMessage(),
-        Common.bannerLabelYes(),
-        Common.bannerLabelNo(),
+        Pylance.pylanceRevertToJediPrompt(),
+        Pylance.pylanceInstallPylance(),
+        Pylance.pylanceRevertToJedi(),
+        Pylance.remindMeLater(),
     );
 
-    if (response === Common.bannerLabelYes()) {
+    if (response === Pylance.pylanceInstallPylance()) {
         commandManager.executeCommand('extension.open', PYLANCE_EXTENSION_ID);
+    } else if (response === Pylance.pylanceRevertToJedi()) {
+        const inspection = workspace.getConfiguration('python').inspect<string>('languageServer');
+
+        let target: ConfigurationTarget | undefined;
+        if (inspection?.workspaceValue) {
+            target = ConfigurationTarget.Workspace;
+        } else if (inspection?.globalValue) {
+            target = ConfigurationTarget.Global;
+        }
+
+        if (target) {
+            await configService.updateSetting('languageServer', LanguageServerType.Jedi, undefined, target);
+            commandManager.executeCommand('workbench.action.reloadWindow');
+        }
     }
 }
 
@@ -37,6 +53,8 @@ export class LanguageServerChangeHandler implements Disposable {
         private readonly extensions: IExtensions,
         private readonly appShell: IApplicationShell,
         private readonly commands: ICommandManager,
+        private readonly workspace: IWorkspaceService,
+        private readonly configService: IConfigurationService,
     ) {
         this.pylanceInstalled = this.isPylanceInstalled();
         this.disposables.push(
@@ -70,7 +88,7 @@ export class LanguageServerChangeHandler implements Disposable {
         let response: string | undefined;
         if (lsType === LanguageServerType.Node && !this.isPylanceInstalled()) {
             // If not installed, point user to Pylance at the store.
-            await promptForPylanceInstall(this.appShell, this.commands);
+            await promptForPylanceInstall(this.appShell, this.commands, this.workspace, this.configService);
             // At this point Pylance is not yet installed. Skip reload prompt
             // since we are going to show it when Pylance becomes available.
         } else {

src/client/activation/node/activator.ts

@@ -47,7 +47,12 @@ export class NodeLanguageServerActivator extends LanguageServerActivatorBase {
             // Pylance is not yet installed. Throw will cause activator to use Jedi
             // temporarily. Language server installation tracker will prompt for window
             // reload when Pylance becomes available.
-            await promptForPylanceInstall(this.appShell, this.commandManager);
+            await promptForPylanceInstall(
+                this.appShell,
+                this.commandManager,
+                this.workspace,
+                this.configurationService,
+            );
             throw new Error(Pylance.pylanceNotInstalledMessage());
         }
     }

src/client/common/utils/localize.ts

@@ -114,10 +114,6 @@ export namespace Pylance {
     export const tryItNow = localize('Pylance.tryItNow', 'Try it now');
     export const remindMeLater = localize('Pylance.remindMeLater', 'Remind me later');
 
-    export const installPylanceMessage = localize(
-        'Pylance.installPylanceMessage',
-        'Pylance extension is not installed. Click Yes to open Pylance installation page.',
-    );
     export const pylanceNotInstalledMessage = localize(
         'Pylance.pylanceNotInstalledMessage',
         'Pylance extension is not installed.',
@@ -126,6 +122,13 @@ export namespace Pylance {
         'Pylance.pylanceInstalledReloadPromptMessage',
         'Pylance extension is now installed. Reload window to activate?',
     );
+
+    export const pylanceRevertToJediPrompt = localize(
+        'Pylance.pylanceRevertToJediPrompt',
+        'The Pylance extension is not installed but the python.languageServer value is set to "Pylance". Would you like to install the Pylance extension to use Pylance, or revert back to Jedi?',
+    );
+    export const pylanceInstallPylance = localize('Pylance.pylanceInstallPylance', 'Install Pylance');
+    export const pylanceRevertToJedi = localize('Pylance.pylanceRevertToJedi', 'Revert to Jedi');
 }
 
 export namespace Jupyter {

src/test/activation/node/activator.unit.test.ts

@@ -17,7 +17,7 @@ import { PYLANCE_EXTENSION_ID } from '../../../client/common/constants';
 import { FileSystem } from '../../../client/common/platform/fileSystem';
 import { IFileSystem } from '../../../client/common/platform/types';
 import { IConfigurationService, IExtensions, IPythonSettings } from '../../../client/common/types';
-import { Common, Pylance } from '../../../client/common/utils/localize';
+import { Pylance } from '../../../client/common/utils/localize';
 
 suite('Pylance Language Server - Activator', () => {
     let activator: NodeLanguageServerActivator;
@@ -92,20 +92,22 @@ suite('Pylance Language Server - Activator', () => {
     test('When Pylance is not installed activator should show install prompt ', async () => {
         when(
             appShell.showWarningMessage(
-                Pylance.installPylanceMessage(),
-                Common.bannerLabelYes(),
-                Common.bannerLabelNo(),
+                Pylance.pylanceRevertToJediPrompt(),
+                Pylance.pylanceInstallPylance(),
+                Pylance.pylanceRevertToJedi(),
+                Pylance.remindMeLater(),
             ),
-        ).thenReturn(Promise.resolve(Common.bannerLabelNo()));
+        ).thenReturn(Promise.resolve(Pylance.remindMeLater()));
 
         try {
             await activator.start(undefined);
         } catch {}
         verify(
             appShell.showWarningMessage(
-                Pylance.installPylanceMessage(),
-                Common.bannerLabelYes(),
-                Common.bannerLabelNo(),
+                Pylance.pylanceRevertToJediPrompt(),
+                Pylance.pylanceInstallPylance(),
+                Pylance.pylanceRevertToJedi(),
+                Pylance.remindMeLater(),
             ),
         ).once();
         verify(commandManager.executeCommand('extension.open', PYLANCE_EXTENSION_ID)).never();
@@ -114,11 +116,12 @@ suite('Pylance Language Server - Activator', () => {
     test('When Pylance is not installed activator should open Pylance install page if users clicks Yes', async () => {
         when(
             appShell.showWarningMessage(
-                Pylance.installPylanceMessage(),
-                Common.bannerLabelYes(),
-                Common.bannerLabelNo(),
+                Pylance.pylanceRevertToJediPrompt(),
+                Pylance.pylanceInstallPylance(),
+                Pylance.pylanceRevertToJedi(),
+                Pylance.remindMeLater(),
             ),
-        ).thenReturn(Promise.resolve(Common.bannerLabelYes()));
+        ).thenReturn(Promise.resolve(Pylance.pylanceInstallPylance()));
 
         try {
             await activator.start(undefined);